In the sector for the design and construction of machines for wrapping packs of products, manufacturers have, over time, used two different construction philosophies, which have led to the definition of two types of machines, respectively automatic and semi-automatic.
These two types originate from a similar basic structure which comprises a support platform for the pallet upon which the group of products to be wrapped rests, and a frame, at the side of the platform, upon which a reel of film for wrapping the group of products is positioned.
In the case of automatic machines, there are solutions which envisage a rotating platform and in which the reel only moves vertically up and down in order to unwind the film along the group of products, or solutions with a fixed platform and a reel which moves vertically and is supported by an arm which rotates about the group of products.
In semi-automatic machines, the first type of system described above for automatic machines is normally used, that is to say, with the rotating platform and a reel which moves in both directions along a vertical axis; these two machines are basically differentiated by the fact that the automatic machines can carry out a series of cycle start and end operations (for example, positioning the free edge of the film near the pack, cutting the film upon completion of wrapping and sealing the edge on the pack thus defined, etc.) using automatic devices and without the direct action of operators on the machine; in contrast, in the case of semi-automatic machines, operators are required in order to carry out said operations.
Obviously, these differences mean that the automatic machines are very expensive, used only for high productivity and are top of the range, whilst the semi-automatic machines are economically better suited to companies with medium-small production levels.